Rename RootWindowHost* to WindowTreeHost*

ui/views/widget/native_widget_aura.cc

Index: ui/views/widget/native_widget_aura.cc
diff --git a/ui/views/widget/native_widget_aura.cc b/ui/views/widget/native_widget_aura.cc
index a5b3f993bcb6f8538b320a772e2b18f3bc4e808c..430124f2a35abe93471789dee43685d19589aa37 100644
--- a/ui/views/widget/native_widget_aura.cc
+++ b/ui/views/widget/native_widget_aura.cc
@@ -683,7 +683,7 @@ void NativeWidgetAura::SetVisibilityChangedAnimationsEnabled(bool value) {
 
 ui::NativeTheme* NativeWidgetAura::GetNativeTheme() const {
 #if !defined(OS_CHROMEOS)
-  return DesktopRootWindowHost::GetNativeTheme(window_);
+  return DesktopWindowTreeHost::GetNativeTheme(window_);
 #else
   return ui::NativeThemeAura::instance();
 #endif
@@ -999,7 +999,7 @@ void CloseWindow(aura::Window* window) {
 #if defined(OS_WIN)
 BOOL CALLBACK WindowCallbackProc(HWND hwnd, LPARAM lParam) {
   aura::Window* root_window =
-      DesktopRootWindowHostWin::GetContentWindowForHWND(hwnd);
+      DesktopWindowTreeHostWin::GetContentWindowForHWND(hwnd);
   CloseWindow(root_window);
   return TRUE;
 }
@@ -1014,9 +1014,9 @@ void Widget::CloseAllSecondaryWidgets() {
 
 #if defined(USE_X11) && !defined(OS_CHROMEOS)
   std::vector<aura::Window*> open_windows =
-      DesktopRootWindowHostX11::GetAllOpenWindows();
+      DesktopWindowTreeHostX11::GetAllOpenWindows();
   std::for_each(open_windows.begin(), open_windows.end(), CloseWindow);
-  DesktopRootWindowHostX11::CleanUpWindowList();
+  DesktopWindowTreeHostX11::CleanUpWindowList();
 #endif
 }